This proposal involves studies by quantitative immunochemical methods of the combining sites of hybridoma antibodies specific for Alpha1 greater than 6 and Alpha1 greater than 3 dextrans, and purification of the Alpha1 greater 6 specific antidextrans in quantities suitable for intensive efforts at crystallization. In addition using recombinant DNA techniques, cDNA clones derived from the H and L chain mRNA of the hybridomas will be sequenced so that specificity differences and X-ray crystallographic data can be correlated with amino acid sequence differences. A set of synthetic Alpha1 greater than 6 glycolipids made by coupling the isomaltose oligosaccharides to stearylamine will be used to produce hybridomas. Their sites will be characterized and studied as above. Rabbit and mouse anti-idiotypic antibodies will be produced to the hybridoma anti-1 yield 6 dextrans and used to define and characterize their idiotypic determinants. Attempts will be made to prepare hybridomas producing monoclonal anti-idiotypic antibodies. Comparison of germ line and expressed genes may make it possible to define the contributions of V, D, J usage, gene conversion and somatic mutation to antibody complementarity and idiotypy.